1. Jackson School of Geosciences Institute for Geophysics University of Texas at Austin Austin TX USA
2. Department of Geological Sciences Jackson School of Geosciences University of Texas at Austin Austin TX USA
3. School of Geosciences University of Oklahoma Norman OK USA
4. Dipartimento di Geoscienze Università degli Studi Padova Padua Italy
5. Istituto Nazionale di Geofisica e Vulcanologia Rome Italy